Application of principal component analysis to the thermal characterization of silanized nanoparticles obtained at supercritical carbon dioxide conditions.

Samples resulting from reaction of TiO(2) with octyltriethoxysilane, developed using a supercritical carbon dioxide procedure, have been studied by infrared and Raman spectroscopies and thermogravimetric analysis. Different reaction conditions have been applied to the preparation of samples in order to study the influence of experimental factors on the sample properties. Vibrational techniques have first been used to verify the presence of silanized structures on the surface of TiO(2) through the detection of specific bands characteristic of the Si-O-Si cross-linking. Thermogravimetric profiles consisting of weight loss values as a function of temperature have been analyzed by principal component analysis to extract information about the characteristics of the linkage between silane and TiO(2) as well as the thermal stability of the prepared materials. The mathematical treatment of data has provided conclusions on the properties of the samples and analogies and differences with respect to the commercial material.